1. Field of the Invention
The present invention relates to a semiconductor device, and particularly to an improvement of the structure of a scribe area of the semiconductor device.
2. Description of the Related Art
In a semiconductor device manufacturing process using a silicon substrate or compound semiconductor substrate, a semiconductor wafer having many individual semiconductor devices formed on the substrate is divided into plural semiconductor chips of individual semiconductor devices by using a dicing saw or the like. An area in which the wafer is divided is called as a scribe area, and the surface of the substrate is normally exposed to the outside in the scribe area.
FIGS. 7A and 7B are plan view and cross-sectional view showing the structure of each scribe area of a wafer or semiconductor device and its peripheral portion as disclosed in JP-1-199434(A) or the like.
As shown in FIGS. 7A and 7B, in the conventional semiconductor device, an interlayer insulating film 2a such as BPSG film or silicon oxide film is formed on a substrate 1, and a passivation film 6a made of an inorganic insulating film of SiON, SiN or the like is formed on the interlayer insulating film 2a to protect the semiconductor device from humid air or corrosive gas. Further, a protection film 7 made of photosensitive or non-photosensitive polyimide resin is formed on the passivation film 6a to buff mechanical stress such as vibration, impact or the like on the substrate and to protect the semiconductor device from environmental humidity.
Reference numeral 10 represents an individual semiconductor device area or semiconductor chip area, and reference numeral 20 represents a scribe area surrounding each semiconductor chip area 10 while being positioned between the neighboring chip areas 10 and extending along the peripheral edge of the neighboring chip areas 10. The scribe area 20 is formed by exposing the surface of the substrate 1 to the outside to divide the wafer into individual semiconductor devices or semiconductor chips. In order to divide the wafer into semiconductor chips, the substrate 1 is scratched or incised along the scribe area 20 with a scriber or dicing saw, and then the principal surface of the substrate 1 is pressed to divide the wafer into individual chips.
In the structure of the scribe area as shown in FIGS. 7A and 7B, however, cracks or fractures which extend to the peripheral portion of the semiconductor chip areas 10 occur on the substrate 1 when the wafer is divided into chips, and thus there occurs such a problem that corners of the individual semiconductor devices are chipped. Further, a semiconductor device characteristics estimating element (not shown) formed in the scribe area is influenced by moisture absorption or the like because the surface of the substrate is exposed to the outside and thus the characteristics of the estimating element are varied, so that the characteristics estimation of the semiconductor device is degraded in reliability.
A method of solving the above problems has been disclosed or suggested in JP-2-45955(A), JP-6-151583(A) and JP-6-77315(A).
The structure of the scribe area disclosed or suggested in JP-2-45955(A) or JP-6-151583(A) will be described with reference to FIGS. 5A and 5B. FIG. 5A is a plan view showing the scribe area, and FIG. 5B is a cross-sectional view taken along A-Axe2x80x2 of FIG. 5A.
As shown in FIGS. 5A and 5B, an interlayer insulating film 2a of a silicon oxide film or the like is formed on the surface of the substrate 1, and a passivation film 6a of a silicon nitride (SiN) film or the like is formed on the interlayer insulating film 2a to protect an estimating element (not shown) formed in a scribe area 20. A rectangular protection film (referred to as xe2x80x9cscribe area protection film patternxe2x80x9d) 7c is formed on the passivation film 6a in the scribe area 20 by a patterning treatment at the same time when a protection film 7 made of organic resin such as polyimide resin or the like is formed on the passivation film 6a in the semiconductor chip area 10 by the patterning treatment. The scribe area protection film pattern 7c is formed so as to protect the estimating element formed in the scribe area 20 and also so that cracks occurring in the substrate at the scribe area during a dicing work for the scribe area after an estimation has been made with the estimating element is prevented from expanding to the semiconductor chip areas 10.
According to JP-6-77315(A), as shown in FIGS. 6A and 6B, it is suggested that a scribe area protection film pattern 7d is disposed in a scribe area 20 so as to be continuous with a protection film 7 of the semiconductor chip area 10 at one side so that cracks occurring in the substrate 1, etc. at the scribe area 20 can be suppressed from expanding to the semiconductor chip areas 10 during the dicing work for the scribe area.
In the technique of forming the protection film pattern of polyimide resin or the like in the scribe area as shown in FIGS. 5A and 5B and FIGS. 6A and 6B, there can be obtained an effect of suppressing the expansion of cracks to the semiconductor chip areas during the dicing work, however, there may occur such a disadvantage that the back surfaces of the semiconductor chips are chipped or a part of the protection film pattern 7c, 7d in the scribe area may remain like beards after the dicing work. Further, this disadvantage also causes reduction of the lifetime of dicing blades.
It is estimated that in the technique of forming the protection film pattern of polyimide resin or the like in the scribe area as shown in FIGS. 5A and 5B and FIGS. 6A and 6B, a larger amount of polyimide resin adheres to the dicing blade as the dicing blade is used for a longer time, so that the dicing efficiency of the dicing blade is lowered and bearded polyimide resin and cracks on the back surfaces of the semiconductor chips are liable to occur.
An object of the present invention is to provide a semiconductor device for which remaining of bearded polyimide resin after a dicing operation and occurrence of cracks on the back surface of an individual semiconductor chip can be suppressed in a semiconductor device dicing process, and particularly to provide the structure of a scribe area of the semiconductor device.
Further, another object of the present invention is to provide a semiconductor device which can enhance the lifetime of a dicing blade in a dicing process of a semiconductor device having a protection film of polyimide resin.
In order to attain the above objects, according to the present invention, there is provided a semiconductor device, comprising a semiconductor substrate having a plurality of individual semiconductor device areas, and a scribe area positioned between the individual semiconductor device areas adjacent to each other so as to extend along peripheral edges of the adjacent individual semiconductor device areas; an interlayer insulating film formed on the semiconductor substrate; a passivation film formed on the interlayer insulating film; and, a protection film formed on the passivation film, wherein the protection film in the scribe area comprises a plurality of first side scribe area protection film patterns formed so as to be continuous with the protection film of one of the adjacent individual semiconductor device areas while being arranged in a direction of the scribe area, and a plurality of second side scribe area protection film patterns formed so as to be continuous with the protection film of the other of the adjacent individual semiconductor device areas while being arranged in the direction of the scribe area, and, both said first side scribe area protection film patterns and second side scribe area protection film patterns are isolated from a center line of the scribe area.
The first side scribe area protection film patterns and second side scribe area protection film patterns may be in axially symmetrical arrangement or in staggered arrangement with respect to the center line of the scribe area.
The interval between the first side scribe area protection film patterns and second side scribe area protection film patterns may be set to 20 to 30% of a width of said scribe area or to 20 to 30 xcexcm.
The shape of the first side scribe area protection film patterns and second side scribe area protection film patterns may be a rectangular, trapezoidal or semicircular shape.
The protection film may be a photosensitive or non-photosensitive polyimide film. The passivation film may be an SiN film or SiON film.
In the scribe area, an alignment mark and/or device characteristics estimating element may be provided.
According to the present invention, the layout of the protection film on the scribe area is set so as to form a plurality of first side scribe area protection film patterns which are continuous with the protection film of one of the adjacent individual semiconductor device areas while being arranged in a direction of the scribe area, and a plurality of second side scribe area protection film patterns which are continuous with the protection film of the other of the adjacent individual semiconductor device areas while being arranged in the direction of the scribe area, for example in an axially symmetrical arrangement or in a staggered arrangement with respect to the center line of the scribe area. With this layout of the protection film on the scribe area, the adhesion of the protection film to a dicing blade can be suppressed to enhance the dicing efficiency and prevent remaining of bearded protection film of polyimide resin and cracks of the back surface of the device area after the dicing operation. Further, since the dicing blade can be prevented from being clogged with the protection film, and thus the lifetime of the blade can be enhanced.